The author would like to thank Xu Zhao and the referees for carefully reading the manuscript and detailed comments. This work was supported by the National Natural Science Foundation of China (Grant No. 11126151) and the Scientific Foundation of Henan University (Grant No. 2012YBZR030).
Let f(z) be a Hecke-Maass cusp form for SL2(Z), and let L(s, f) be the corresponding automorphic L-function associated to f. For sufficiently large T, let N(σ, T) be the number of zeros p =β + iγ of L(s, ...